Abstract: An expansion device includes a casing and a wireless transceiving module. The casing includes a receiving slot suitable for accommodating a mobile communication device, wherein the mobile communication device includes at least an antenna to operate at least one communication band. When the mobile communication device is accommodated in the receiving slot, the wireless transceiving module receives electromagnetic wave at the communication band, generates at least one radio frequency signal, and wirelessly couples the radio frequency signal to the antenna in the mobile communication device.

Abstract: An antenna module is disclosed. The antenna module comprises a first conductive unit, a second conductive unit and a third conductive unit. The first conductive unit has a feeding point. The second conductive unit is disconnected with the first conductive unit electrically. The third conductive unit is disposed adjacent to the first conductive unit and electrically connected with the second conductive unit.